1. Technical Field
The present invention relates to a gem-dinitro ester energetic material, which is synthesized using esterification, and to a preparation method thereof.
2. Description of the Related Art
A plastic bonded explosive (PBX) has been developed to improve both performance and insensitivity of explosives, and typically includes a molecular explosive in crystalline form, such as RDX (Research Department Explosive), which typically exhibits explosive performance, and a binder system. The binder system is used in an amount of about 2˜20 wt % based on the total weight of PBX, and functions to impart dimensional stability and insensitivity to the molecular explosive in crystalline form. However, it does not contain a nitro group for exhibiting explosive performance as in the molecular explosive, thus deteriorating the total performance of the explosive.
The binder system is composed of a polymer and a plasticizer. As such, the amount of the plasticizer is as large as about three times the amount of the polymer, and thus the properties of the plasticizer are regarded as very important.
In order to maximize performance of PBX, thorough research into introduction of a nitro group to a plasticizer is ongoing, and a plasticizer having a nitro group is referred to as an energetic binder. The energetic binder has been extensively and intensively studied, but a typical example of the plasticizer, which is actually applied to explosives, includes a formal or acetal plasticizer, such as bis(2,2-dinitropropyl)formal (represented by Chemical Formula A below) or bis(2,2-dinitropropyl)acetal (represented by Chemical Formula B below).

Preparation of PBX requires a mixing process. The mixing process is typically performed at 60° C. to decrease the viscosity of a polymer. The molecular explosive such as RDX used for PBX is shape-controlled in a polygonal form through recrystallization to maintain insensitivity to external impact. However, when the mixture comprising the shape-controlled molecular explosive and the energetic plasticizer mixed at 60° C. is cooled to room temperature, the shape-controlled molecular explosive is dissolved in the plasticizer and then produced again in the form of crystals. In this procedure, the molecular explosive is changed to an undesired crystal shape, such as a needle shape, etc., instead of a polygonal shape. Like this, in the case where the molecular explosive having a changed shape is contained in PBX, sensitivity of PBX increases.
The sensitivity of PBX by the plasticizer as above is based on the chemical structure of the plasticizer. Specifically, a structural difference between DOA and the energetic plasticizer depends on whether a nitro group which is an energy group is contained. When a nitro group is introduced to the plasticizer, a solid filler such as a molecular explosive is dissolved in the mixing process at 60° C. due to strong polarity of the nitro group. When the temperature is lowered, the molecular explosive is deposited again as a solid. In the deposition procedure, because the shape of the molecular explosive is changed to a sensitive shape, the molecular explosive having a changed shape makes PBX sensitive.